Flame shaper and luminosity control



June 8, 1965 L. L RN 3,187,523

FLAME SHAPER AND LUMINOSITY CONTROL Filed Oct. 7, 1963 ber 7, 1963.

relatively small pilot light United States Patent V 3,187,523 v I FLAME SHAPER AND LUMINQSITY CONTRGL Eugene L. Kilbourn, Marengo Township, Calhoun County, Mich, assignor to S. H. Leggitt Company, Marshall, Mich., a corporation of Michigan Filed Oct. 7, 1963, Ser. No. 314,393 12 (Ilaims. (Cl. 67-87) This invention relates to a device for shaping a flame and for directionally controlling the eflective light output thereof.

The device of the invention wasdeveloped for use in a gas-fueled highway warning light such as that shown in my copending application SerialNo. 314,392, filed Octo- Briefly, said warning light'includes a single burner yielding a constant pilot flam'eand fed by an intermittent main fuel supply which is ignited by the pilot to provide an intermittent main flame. Accordingly, the particular embodiment of the invention hereinafter disclosed will be that utilized in such a warning light and reference will be made thereto for the purpose of convenience in description. However, it will be understood that the device of the invention is applicable also in situations differing from such a warning light.

Several problems involving the protection or control of a flame have been encountered in past flame utilizing constructions including the aforementioned warning light. For example, constructions are known which utilize a for igniting a larger main flame wherein said pilot light, because of its small size and the small quantity of gaseous fuel supplied thereto, is relatively easily extinguished by curents in the surrounding atmosphere. The pilot is more difficult to maintain when fuel consumption 'by the pilot is to be minimized or when, as in the aforementioned highway warning light, a pilot light of very small size and visibility is desirable to maximize the contrast between the on and off conditions of the flashing main flame.

Previous constructions incorporating lenses, particularly heat-sensitive plastic lenses, for transmitting and controlling light from a flame have had damaged lenses due to overheating thereof by theflame whose light they are to control. Furthermore, devices such as the aforementioned warning light, which include a pair of spaced coaxial lenses centered on the flame, have been hindered because the main flame thereof has generally been of circular cross section and has presented a relatively narrow area to the lenses whereby a relatively small quantity of light emerges from said lenses.

Hence, the objects of this invention include:

(1) To provide a device for shaping a flame and for controlling the light output thereof. I

(2) To provide a device, as aforesaid, particularly adapted to gas-fueled warning lights of the type incorporating a continuously burning pilot light and anfiinterrnittently burning main flame, both of which flames emanate from the same burner.

(3) To provide a device, as aforesaid, for protecting a pilot light from being blown out by wind or the like.

(4) To provide a device, as aforesaid, for use on a device employing a relativelylarge or mainflame for pro- Ice the width and area of said flame as seen from said direction.

(7) To provide a device, as aforesaid,which is adjustable to control the completeness of combustion of the fuel within the flame and thereby cause an increase or decrease in the brightness of said flame (8) To provide a device, as aforesaid, which may be constructed from relatively inexpensive material with a minimum of equipment and a minimum of operations performed thereon, which may be mass produced in a factory or made singly by unskilled personnel with simple tools, which is of one-piece construction and whichis manufacturable from sheet material with only severing and bending operations. i

(9) To provide a device, as aforesaid, which requires little or no maintenance during use, which is easily replaced at a nominal cost, which has a long service life, which is adjustable to meet a wide variety of flame control requirements and which is adaptable to a Wide variety of flame utilizing devices. I

Other objects and purposes of the invention will become apparent to persons acquainted with apparatus of this general type upon reading the following disclosure and inspecting the accompanying drawings.

In the drawings: i

FIGURE 1 is an isometric view of a device embodying the invention.

FIGURE 2 is a FIGURE 1.

FIGURE 3 is a sectional view on the line III-III of FIGURE 2.

FIGURE 4 is a sectional view on the line IV-IV of FIGURE 2.

FIGURE .5 is atop elevational view and discloses the device of FIGURE 1 previous to the bending thereof into its configuration of FIGURE 1.

Certain terminology will be used in the following dc.-

top elevational view of the device of scription for convenience in reference only and is neither tecting said flame against distortion and movement thereof caused by wind or the like and toincrease the constancy and average level of illumination yielded thereby.

(5) To provide a device, as aforesaid, useful on devices employing parts, such as plastic lenses, susceptible to heat damage by a nearby flame, said device reshaping said flame to reduce its dimensional extent toward said lenses.

(6) To provide a device, as aforesaid, for use in conjunction with an illuminating flame which provides maximized illumination in a preferred direction byincreasing elieved nor intended to :be limiting. For example, the

' terms upward and downward will have reference to the device of the invention in its normal position of operation, as appearing in FIGURES l, 3 and 4. The terms inward and outwar will refer to the geometric center of the device appearing in the drawings. Such terminology will include the words above specifically mentioned, derivatives thereof and words of similar import.

Referring now to the drawings, the flame shaper and luminosity control 19 therein illustrated as embodying the invention is preferably constructed from a single piece of perforate, heat-resistant material. Said material may be, for example, wire screening, expanded metal, or perforated sheet metal. The device 10 includes a planar, generally rectangular, base portion 12 having a preferably centrally located opening 23 therein for the insertion upwardly therethrough of a suitable burner 24 (FIGURE 3) The burner 24 is here shown as being affixed to the device It) by a suitable nut 26. A pair of preferably identical and preferably planar tabs 13 and 14 extend from the base portion '12 at preferably parallel lines 2-1 and 2.2 and converge upwardly and inwardly toward each other. i The'upper ends of the tabs 13 and 14 are spaced apart over the opening 23. Ina particular embodiment, the angle of the tabs 13 and 14 with the base portion 12 was advantageously found'to be 45 degrees. A pair of trapezoidally shaped side panels 27 and 28 meet the base portion 12 along their respective major base lines 3-1 and 32, which base lines are perpendicular to the lines 21 and Z2 mentioned hereinabove and are centered on the opening 23. The panels 27 and 28 extend convergingly upwardly from the base portion 12. In a particular embodiment, the side panelsZZ and 28 were each inclined to the base portion 12 at an angle of degrees. The

. ity, while still allowing upper corners of the tabs f3 and 14 lie adjacent to and may contact the inner surfaces of the side panels 27 and 23 but are separated whereby a flame emanating from the Operation The device of the invention may advantageously be manufactured from a planar sheet 39 of perforate material (FIGURE 5) of generally rhombic shape. The hole 23 and suitable slits 16,17,18 and 19 defining the sides of the tabs .13 and 14 may be cut in the sheet 3? by any convenient means. The tabs 13 and 14 may then be folded upwardly and toward each other along the respective lines 2 1 and 2 2-to their positions shown in FIGURE 1. The

- side panels'27 and 28 may then be folded along the lower or major base lines 31 and 32 upwardly and toward each other andthe cats 36 and 37 may then be folded outwardly away from each other along the upper base lines 33 and 34 to complete theconstruction of the device 10. When the device of the invention is installed on a burner 24 which is-en'ii-tting' a relatively small or pilot flame, here inidcated by the broken line 41 (FIGURES 3 and 4), said pilot flame 4 1 will be (protected from wind or other air movements by the adjacent portions of the side panels 27 and 28 and by the tabs '13 and 14. The tabs 13 and 14, further, tend to decrease somewhat the visibility of the pilot flame. The tabs 13 and 14 preferably have their upper ends spaced a distance apart approximating the diameter of the pilot flame and have their upper edges of length equal to or greater than said-diameter whereby said upper edges and the adjacent parts of the side panels 27 and 28 define an opening 42 (FIGURE 2) for emitting the exhaust gases from the pilot flame 41. Spaces between the tabs 21 and 22 and the side walls 27 and 28 such as one indicated at 43 (FIGURE 4) allow entrance of air required for combustion by the pilot flame 41 but are so positioned that a gust of air will enter on a line which does not pass through the pilot flame 4 1 and so does not blow same out. The perforate material from which the device is constructed reduces the velocity of air currents passing therethrough, particularly when said currents are of relatively high veloclow velocity passage of air therethrough for combustion. Increasing the rate of gas flow to the burner 24 increases the height of the flame thereof as indicated by the broken line 44 (FIGURES 3 and 4). It has been found that when the flame 44 is sufiiciently highthat its upper portion is between the ears 36 and 37, said ears lying close to the normal perimeter of the flange at the lines 33 and 34, that the edges of said flame 44 nearest said cars 36 and 37 will tendto follow the upwardly divergent path thereof. Thus, when the apparatus is viewed from the point of view of FIGURE 4, said flame will be spread out over a larger area than would normally be the case. This larger area is compensated for as indicated in FIGURE 3 by a concurrent narrowing of the flame in a plane perpendicular to the planeof the broadened flame face. Although the precise reasons-for this behavior are not fully understood,

, it is hypothesized that the heat-conducting properties of the perforate metal sheet reduce the temperature of and hence contract the air bounding the ears 3'6 and 37 adjacent the flame 44 thereby creating an effective low pressure area at the surface of the ears 36 and 37 adjacent the flame. On the other hand, the expanding gases within the flame are at va'high'er pressure and the pressure drop thus created causes the gases constituting the flame to spr'e'adtoward the ears 36'and 37. Since at any moment the quantity of combusting gases is constant, the spreading of the flame in one direction requires a thinning of the flame in another direction, here along a plane perpendicular to the broadened flame front and extending upwardly from the burner. The upwardlyconvergent edges of the ears 36 and 3''! lessen the effect of saidears on said flame near the tops thereof whereby the top of the flame ceases to follow the ears upward divergence/and said flame top is thus made upwardly convex. Hence, the shape of the flame more closely approximates a circlefor, as an example, providing an improved image shape for a circular lens.

Hence, by pinchingthe ears 36 and 37 together, the flame will be narrowed and by spreading them apart, the flame will be broadened. Thus, a wide, flat flame can be obtained which will direct a majority of its light in directions perpendicular to its flat sides but relatively little light in directions parallel to its flat sides. Hense, maximum effective illumination may be obtained in desired directions by sacrificing illumination in other directions. Thus, in a warning light including such a flame shaping and luminosity control device .10, the light transmitting lenses thereof would normally be placed parallel to said flat faces of the flame to maximize the amount of light to be transmit-ted thereby. Further, the surface of the flattened flame is slightly farther away from the lens than would be a normal or circular sectioned flame thereby reducing to some extent undesirable heat effects on the lens by the flame. I

It was noted during the development of this device that spreading of the ears 36 and 37, as by decreasing the angle between said ears and their respective side plates 27 and 28 along the respective lines 33 and 34, causes the flame to widenstill further. For some reason, however, the combustion deteriorates in quality when said ears are spread. Since a highly luminous flame is obtained by having large numbers of incandescent carbon particles therein and since this condition is in turn obtained by having relatively poor combustion, a flame of maximum luminosity may therefore be obtained by spreading the ears 36 and 37 to a maximum distance which is limited by the amount of smoke which may be tolerated from the flame, said flame getting .smokier as com-bustion decreases in quality. Thus, not only can the area of the flame be con-trolled but the brightness thereof may also be controlled by varying the angle and distance between the ears36 and 37.

Although a particular preferred embodiment of the invention has been disclosed hereinabove for purposes of illustration, modifications or variations thereof lying within the scope of the appended claims, are fully contemplated.

What is claimed is:

1. flameshaper and luminosity control for a flame, comprismgz an opposed, spaced pair of perforate side panels extendin'gconvergingly upwardly for defining an opening there between for enclosing the lower part of said flame;

a pair of perforate ears disposed atop and extending divergent'ly upwardly from said .side panels for spreading the upper part of said flame therebetween.

2. The device defined in claim =1 wherein said ears have side edges which converge upwardly for producing a convex upper flame edge.

3. The device defined in claim 1 wherein said ears define'an included angle of approximately 30 degrees therebetween.

4. The device defined in claim 1 wherein said perforate material is wire screening.

5. The device defined in claim 1 including a base portion lying between and joining the lower edges of said side panels, said base portion having an opening therethrough and between said side panels for admitting said flame therethrou'gh and a pair of upwardly converging tabs of perforate material affixed to said base portion between said side panels, said, tabs being disposed on r J opposite sides of said opening and having spaced top edges for allowing passage of said flame upwardly therefined between said tabs and said side panels adjacent said base portion for admitting air to said small flame; and

wherein said side panels and base portion extend outvwardly considerably beyond said tabs for preventing wind from entering said gaps along lines connecting ones of said gaps diagonally opposed across said opening.

8. The device defined in claim wherein said tabs each make an angle of approximately 45 with said base portion and said side panels extend upwardly beyond said top edges of said tabs whereby said tabs tend to conceal a low flame but reveal a high flame for increasing the diflerence in illumination aflorded by such flame.

9. A luminosity control for a flame including:

a burner and a pair of upwardly extending, convergently sloped tabs and means for fixing said tabs on opposite sides of said burner, the upper edges of said tabs defining a first slot through which the burner flame extends; r

a pair of upwardly divergent, spaced ears of perforate material spaced above and approximately centered on said burner whereby said flame tends to spread toward said ears;

said ears having opposed, spaced bottom edges defining a second slot through which said burner flame extends, said second slot being spaced above said first slot and extending at right angles thereto;

means fixed with respect to said ears and with respect to said burner for allowing the angle of divergence between said ears to be increased or decreased for changing the combustion efiiciency of said flame so that an increase in said angle of divergence causes a brighter flame.

10. A flame shaper and luminosity control for a lamp burner comprising:

a sheet of wire screening including a rectangular central portion and a pair of symmetrical triangular side portions having side edges extending convergently to vertices spaced from the opposed length edges of said central portion, said side portions being folded along said length edges with respect to said central portion and extending convergently upwardly at an angle of about 80 to said central portion, said side portions :being bent outwardly at locations spaced above said central portion at an included angle of about 30 to define a flame spreading zone above said locations;

an opening through and centered on said central portion for reception therethrough of said burner;

a rectangular tab located at each end of and integral with said central portion, each of said tabs being defined by a pair of spaced slits equally spaced from and parallel to corresponding ones of said length edges of said central portion and extending from the outer edge of said sheet to points spaced from said central opening and a fold line perpendicular to said length edges connecting said points of each pair of slits, said tabs extending convergently upwardly from said fold lines at an angle of about 45 with said central portion and lying closely adjacent said side sheets at a distance below said locations, the upper ends of said tabs being spaced apart above said opening for admission of a flame from said burner therebetween and being spaced below said locations on said side sheets;

whereby said tabs and the part of said side portions below said locations protect a flame issuing from said burner from being blown out while the parts of said side portions above said locations spread said flame therebetween. r

11. A flame shaper for a lamp burner comprising:

a pair of similar,perforate side sheets and means for supporting said side sheets in opposed, spaced relation for receiving said burner therebetween, each of said side sheets having a substantially upstanding lower portion and an outwardly and upwardly directed upper portion, each of side sheets narrowing toward its upper end, said outwardly directed upper portion spreading the flame of said burner therebetween.

12. A flame shaper and luminosity control for a lamp burner comprising: i

a sheet of wire screening having a rectangular midportion and a pair of substantially identical, symmetrical side portions integrally connected thereto along an opposed pair of side edges of said midportion, said side portions being folded along said side edges with respect to said midportion and extending substantially upwardly therefrom, said side portions tapering from said midportion toward the upper ends thereof, said side portions being bent outwardly at locations spaced above said midportion at an acute included angle to define a flame spreading zone above said locations;

an opening through and centered on said midportion for reception therethrough of said burner;

a rectangular tab integral with said midportion along each of the remaining pair of edges of said midportion, said tabs extending convergently upwardly from said remaining edges and lying closely adjacent said side sheets at a distance below said locations, said side portions extending longitudinally beyond said 'midportion along said side edges at least by the approximate length of said tabs, the upper ends of said tabs being spaced apart above said opening for admission of a flame from said burner therebetween and i being spaced below said location on said side sheets; whereby said tabs and the part of said side portions below said locations protect a flame issuing from said burner from being blown out while the parts of said side portions above said locations spread said flame.

References Cited by the Examiner UNITED STATES PATENTS EDWARD J. MICHAEL, Primary Examiner. 

1. A FLAME SHAPER AND LUMINOSITY CONTROL FOR A FLAME, COMPRISING: AN OPPOSED, SPACED PAIR OF PERFORATE SIDE PANELS EXTENDING CONVERGINGLY UPWARDLY FOR DEFINING AN OPENING THERE BETWEEN FOR ENCLOSING THE LOWER PART OF SAID FLAME; A PAIR OF PERFORATE EARS DISPOSED ATOP AND EXTENDING DIVERGENTLY UPWARDLY FROM SAID SIDE PANELS FOR SPREADING THE UPPER PART OF SAID FLAME THEREBETWEEN. 